Heat exchanger



y 20, 1955 J. R. VAN GEUNS ETAL 3,195,623

HEAT EXCHANGER Filed Aug. 28, 1962 M w I:

INVENTOR JOHANNES R.VAN cams JOHANNES vAfi DER STER AGE United States Patent 4 'l is.

3,195,621 HLAT EhZtIHANGER .ler nnes Rudoiphus and l ohannes van dcr Sh lmmasingel, even, Netherlands, assign-sis to North Amer a lies (lompany, Inc, New York, ll.Y., a corporation of'lhcinware Filed Aug. 28, 1962, Set. No. 219,831 Claims priority, application Netherlands, Sept. 1?, 1261, 269,394 (Ilaims. (Qt. Edd -ltd) The invention relates to a heat exchanger comprising a filling mass capable of absorbing heat and giving off heat and arranged in a housing, this filling mass being traversed alternately in one direction by a medium to be cooled and in the other direction by a medium to be heated, which media to be cooled and to be heated having dififerent thertrial-capacity flow intensities, said heat exchanger being adapted to reflux part of the medium having the higher thermal-capacity flow intensity said part being being such that the heat exchanger is thermally balanced.

It is known to balance a heat exchanger traversed in one direction by a medium having a higher thermal-capacity flow intensity than the medium flowing through it in the other direction by refluxing part of the medium having the higher thermal-capacity flow intensity through the heat exchanger. This reflux medium thus gives off part of the heat absorbed from the heat exchanger to this heat exchanger or, if the cooled medium is refluxed partly through the heat exchanger, the reflux medium absorbs part of the heat given off to the heat exchanger.

The term thermal-capacity flow intensity is to denote herein the product of the specific mass, the specific heat and the volume of the medium passing through the heat exchanger per unit time.

Balancing of a heat exchanger is important with respect to maintaining at least substantially constant outlet temperatures of the media passing alternately through the heat exchanger. Balancing is furthermore important with a view to self-cleaning of the heat exchanger. If the flow of medium in one direction is capable of absorbing less heat than the other flow of medium has given off to the heat exchanger, said flow of medium will not be capable of removing completely from the heat exchanger the solid products dissociated from the other medium such as ice or carbon-dioxide snow. The known heat exchangers, in which part of one of the passing media is refluxed through the heat exchangers, have all comparatively complicated and expensive structures and exhibit, in addition,

the disadvantage that the heat transmission from the me dium flowing back through the heat exchanger to the heat exchanger is comparatively low.

The heat exchanger according to the invention has a comparatively simple, compact construction, in which a satisfactory heat transmission between the reflux medium and the heat exchanger is obtained. This heat exchanger is characterized in that the filling mass is in satisfac tory thermal contact with the inner side of the housing containing the filling mass, said housing being provided at its outer surface with surface-enlarging structural parts of satisfactory thermal conductivity, the heat exchanger comprising a further housing which surrounds the housing comprising the filling mass with a given amount of play so that at least part of the medium passing through the heat exchanger in one direction can flow back between the walls of the said two housings.

In this manner a reflux channel for the medium is obtained in a simple manner along the circumference of the filling mass. The medium flowing back through this channel gives oil heat or absorbs heat on the outer wall of the housing comprising the filling mass. The heat transice mission between the housing and the refluxed medium is affected very advantageously by providing the surface of the housing with surface-enlarging structural parts of satisfactory thermal conductivity. These parts may be formed, for example, by vanes, ribs or pins.

In an advantageous embodiment of the heat exchanger according to the invention the said structural parts enlarging the surface may be formed by a wire wound helically around the housing and fastened to the housing, preferably by soldering and made from a material of satisfactory thermal conductivity, for example copper.

The refluxed medium must absorb or give off heat from or respectively to the housing comprising the filling mass and this heat must be passed on to the filling mass or be withdrawn from this filling mass respectively.

To this end the heat exchanger according to the invention is characterized in that the filling mass is built up from stacked layers of metal gauze, which gauze is soldered to the wall of the housing concerned.

The conjunction of two housings, one of which surrounds the other with a given amount or" play, while the inner housing comprises the filling mass, which is soldered to the inner wall of the housing, the outer side of which is provided with a copper wire helically wound around the housing and soldered thereto, provides an extremely simple structure of a heat exchanger of the kind set forth.

A further advantageous embodiment of the heat exchanger according to the invention is characterized in that the reflux channel between the two housings of the heat exchanger is in open communication on one side with the outlet duct for the medium having the higher thermalcapacity flow intensity, while at least part of said medium can flow back through the reflux channel in opposite direction, the reflux channel being provided with a closing member which closes the passage of the channel, when the medium flow is reversed.

The invention will now be described more fully with reference to the drawing, which is not drawn according to scale and is to be considered by way of example only.

FIG. 1 is an axial sectional View of a heat exchanger in which part of the medium passing in one direction through it can be refluxed in opposite direction through this heat exchanger.

FIG. 2 shows a variant of the heat exchanger of PEG. 1 also in an axial sectional view.

Referring to FIG. 1, reference numeral ll designates a filling mass, which is arranged in a housing 2 and which is closed at both ends by perforated metal plates 3 and 4. Around the outer side of the housing 2 a wire 5 of satisfactory thermal conductivity, for example of copper, is wound helically and fastened to the housing 2 by a soldering joint of satisfactory thermal conductivity. The filling mass 1 is built up from metal gauzes having a circumference at least substantially equal to that or" the inner side of the housing 2, the metal gauzes also being fastened to the inner side of the housing 2 by a soldering joint of satisfactory thermal conductivity. The heat exchanger comprises furthermore a second housing 6, which surrounds the housing 2 and the wire 5 surrounding it with a given amount of clearance, so that between these two housings an annular channel 16 is left. The heat exchanger is furthermore provided on its upper side with a lid '7, with which communicates a medium inlet or outlet duct 3 and which is furthermore provided with medium outlet ducts 9 for the medium flowing back between the housings Z and 6. The lower side the heat exchanger is provided with a lid it), which is provided with a medium inlet or outlet duct 11, while between the duct fl and the channel between the housings 2 and 5 there is provided a duct 12. This duct 12 comprises a controllable closing member 13. Between the lids 7 and 1t) and the housing 2 sealing rings 14 and 15 are provided.

The device operates as follows. The hotter medium passing through the heat exchanger in the direction of the arrow A gives off heat to the filling mass 1 during passage. Part of this medium is conducted back in a direction opposite the arrow A, after passing through the filling mass 1, out of the duct 11 via the control-member .13 and the duct 12, through the channel 16 between the housings 2 and 6. During the reflux the medium absorbs some heat from the wire 5 wound on the housing 2 which heat is extracted via the housing from the gauzes of the filling. The reflux medium leaves the heat exchanger through the ducts 9, which may open out, if desired, in the medium outlet duct 11. When the heat exchanger is reversed, a cold medium flow passes in the direction of the arrow B through the heat exchanger. It is sup-posed in this case that the thermal-capacity fiow intensity of this medium is lower than that of the hotter medium passing through the heat exchanger in the direction of the arrow A. It

will be obvious that, when the colder medium passes through the heat exchanger, the closing member 13 must be closed, so that no medium can pass through the chan-' nel between the two housings 2 and 6.

Referring to FIG. 2, reference numeral 21 denotes a filling mass which is built up similarly to the filling mass 1 of FIG. 1. The filling mass 21 is arranged in a housing 22 and soldered to the inner side thereof; at both ends the housing 22 is closed by perforated plates 23 and 24; Around the outer side of the housing 22 a copper wire 25 is wound helically and soldered to said housing 22. The heat exchanger comprises furthermore a housing 26, which surrounds the housing 22 with a clearance, so that between these two housings again a reflux channel 36 is left. is limited by a lid 27, with which communicates a medium outlet or inlet duct 28 and with which communicate furthermore a number of ducts through which the medium conducted back through the channel between the housings 22 and 26 can be conducted away. On the lower side the heat exchanger is bounded by a lid 30, with which communicates a medium outlet or inlet duct 31. The ducts 29 are in open communication with the duct 31. The housing 22 is rigidly secured'to the lid 27 and a sealing member 34 is provided between these parts.

'From the drawing it will be seen that in this embodiment the reflux channel 36 between the housings 22 and 26 is in open communication with the medium outlet duct 31. When a medium is passed in the direction of the arrow A through the heat exchanger, part of it can flow through the channel 36 between the housings 22 and 26 via the by-pass valves to the ducts 29, through which it is passed back to the medium outlet duct 31. However, when a medium is passed through the heat exchanger in the direction of the arrow B, the by-pass valve 35 is closed, so that no medium can flow through the channel between the housings 22 and 26. It will be obvious that in this case the duct 31 must include a control-member capable of checking the value of the flow of medium through the ducts 29.

What is claimed is:

1. A heat exchanger comprising an interior housing, a combination heat-absorbing and heat-emitting filling mass in said interior housing, said filling mass being traversed alternately in one direction by a medium to be cooled and inthe other direction by a medium to be heated, means so arranged that with different thermal capacity how in- On the upper side the heat exchanger (g, tensities of the media to be cooled and heated, such part of said medium having the higher thermal capacity flow intensity can be passed back and in thermal contact with said interior housing, said heat exchanger being provided at spaced locations with separate ducts, said ducts includ ing valve mean which when operative connect the ducts alternately with said medium to be heated and with said medium to be cooled whereby said medium traverses said filling mass alternately in opposite directions, said filling mass being in heat exchanging contact with the inside of said interior housing, said means including a thermally conductive surface-enlarging structural part provided on the outside surface or" said interior housing, and an exterior housing surrounding but spaced from said interior housing forming a channel therebetween for at least a part of said main flow of medium passing in one direction through said heat exchanger to How back in an opposite direction and in contact with said structural part whereby heat is extracted from said'filling mass and said heat exchanger is balanced.

2. A heat exchanger as claimed in claim 1 wherein said surface-enlarging structural part is a wire of good thermal conductivity wound helically' around the outside surface of said interior housing and secured thereto.

3. A heat exchanger as claimed in claim 1 wherein said filling mass is constituted of stacked layers of metal gauze, said mass being secured to the inside of-said interior housing. 7

4. A heat exchanger comprising an interior housing, a combination heat-absorbing and heat-emitting filling mass in said interior housing, said filling mass being traversed alternately in one direction by a medium to be cooled and in the other direction by a medium to be heated, means so arranged that with different thermal capacity flow intensities of the media to be cooled and heated such part of said medium having the higher thermal capacity flow: intensity can be passed back and in thermal contact with said interior housing, said heat exchanger being provided at spaced locations with separate ducts, said ducts including valve means which when operative connect the ducts alternately with said medium to be heated and with said medium to be cooled whereby said medium traverses said filling mass alternately in opposite directions, said filling mass being in heat exchanging contact with the inside of said interior housing, said means including a thermally conductive surface-enlarging structural part provided on the outside surface of said interior housing, an exterior housing surrounding but spaced from said interior housing forming a channel therebetween for at least a part of said main flow of medium passing in one direction through said heat exchanger to flow back in an opposite direction and in contact with said structural part whereby heat is extracted from said filling mass and said heat exchanger is balanced, an outlet duct, said channel being on one side in open communication with said outlet duct for the medium having the higher thermal capacity flow intensity, and a closing member in said channel which closes the passage of said channel when said main flow of medium isreversed. 1

References Cited by the Examiner UNITED STATES PATENTS 7 1,717,103' 6/29 Godel 55-28 X 2,964,298 12/60 McIntosh et al -7 3,100,523 8/63 Marrujo 16516 3 X CHARLES SUKALO, Primary Examiner. 

1. A HEAT EXCHANGER COMPRISING AN INTERIOR HOUSING, A COMBINATION HEAT-ABSORBING AND HEAT-EMITTING FILLING MASS IN SAID INTERIOR HOUSING, SAID FILLING MASS BEING TRAVERSED ALTERNATELY IN ONE DIRECTION BY A MEDIUM TO BE COOLED AND IN THE OTHER DIRECTION BY A MEDIUM TO BE HEATED, MEANS SO ARRANGED THAT WITH DIFFERENT THERMAL CAPACITY FLOW INTENSITIES OF THE MEDIA TO BE COOLED AND HEATED, SUCH PART OF SAID MEDIUM HAVING THE HIGHER THERMAL CAPACITY FLOW INTENSITY CAN BE PASSED BACK AND IN THERMAL CONTACT WITH SAID INTERIOR HOUSING, SAID HEAT EXCHANGER BEING PROVIDED AT SPACED LOCATIONS WITH SEPARATE DUCTS, SAID DUCTS INCLUDING VALVE MEANS WHICH WHEN OPERATIVE CONNECT THE DUCTS ALTERNATELY WITH SAID MEDIUM TO BE HEATED AND WITH SAID MEDIUM TO BE COOLED WHEREBY SAID MEDIUM TRAVERSE SAID FILLING MASS ALTERNATELY IN OPPOSITE DIRECTIONS, SAID FILLING MASS BEING IN HEAT EXCHANGING CONTACT WITH THE INSIDE OF SAID INTERIOR HOUSING, SAID MEANS INCLUDING A THERMALLY CONDUCTIVE SURFACE-ENLARGING STRUCTURAL PART PROVIDED ON THE OUTSIDE SURFACE OF SAID INTERIOR HOUSING, AND AN EXTERIOR HOUSING SURROUNDING BUT SPACED FROM SAID INTERIOR HOSUING FORMING A CHANNEL THEREBETWEEN FOR AT LEAST A PART OF SAID MAIN FLOW OF MEDIUM PASSING IN ONE DIRECTION THROUGH SAID HEAT EXCHANGER TO FLOW BACK IN AN OPPOSITE DIRECTION AND IN CONTACT WITH SAID STRUCTURAL PART WHEREBY HEAT IS EXTRACTED FROM SAID FILLING MASS AND SAID HEAT EXCHANGER IS BALANCED. 